1. Field of the Invention
The present invention relates to mounting an optical element onto a mounting substrate, and an optical module that optically couples the optical element and an optical fiber.
2. Description of the Related Art
High optical coupling efficiency and low loss are demanded of optical modules that couple optical fibers and optical elements such as light emitting elements and light receiving elements. Thus, mounting that includes high-precision optical axis alignment is required.
As one such optical coupling structure, for example, a configuration has been disclosed where a V-groove is formed on a substrate. An optical fiber is run along the V-groove and fixed in the V-groove through a support guide substrate. By disposing an edge-emitting type light emitting element array at an end of the optical fiber and the side of the support guide, the optical fiber and the light emitting element are optically coupled along the optical axis running in direction along the length of the V-groove (see, for example, Japanese Patent Laid-Open Publication No. H8-201664).
Nonetheless, with the technology above, since both the light emitting element array and the optical fiber are structures mounted on the V-groove of the substrate, optical axis alignment with respect to all 3 directions along X, Y, and Z axes is required. The optical fiber is accommodated inside the V-groove, while the light emitting element array is mounted on the V-groove. However, even if the optical axis of the center (core) of the optical fiber is along the X axis, positioning of the light emitting element array disposed on the V-groove is not performed using the V-groove and therefore, optical axis alignment with respect to the X, Y, and Z axes is required between the optical fiber and the light emitting element array.
Since a V-groove such as that above accommodates an optical fiber along the X axis, from the perspective of the optical fiber alone, there is, conversely, no degree of freedom with respect to the Y and Z axes, making optical axis alignment by moving the optical fiber side difficult. The V-groove, when disposed in parallel and in plural to accommodate multiple optical fibers, is suitable for optical coupling between the optical axes of the optical fibers and the light emitting element array disposed at the pitch of the V-groove. However, with respect to alignment of an optical fiber and an optical element along a single optical axis, consequent to the limited degree of freedom, the V-groove is unsuitable for high-precision optical coupling.
Additionally, for a structure where in addition to a light emitting element, a wavelength converter element, for example, is disposed as an optical element mounted to an optical module, the number of optical coupling sites increases, whereby an equivalent number of optical axis alignments becomes necessary.
In the description above, although optical coupling of optical fibers and optical elements has been described, when an optical waveguide is formed on a substrate, and the optical waveguide and an optical fiber are optically coupled, easy and high-precision optical axis alignment of the optical waveguide and the optical fiber is desirable in this case as well. Furthermore, for reductions in the size of an apparatus that includes the optical module, fewer components and an overall smaller size are preferable.
To solve the problems related to the conventional technologies above, one object of the present invention is to provide an optical module that enables high-precision assembly by a simple configuration and reductions in size.